Traffic benefits from the Basin Flyover are reliant on a whole package of improvements - not just the bridge, a board of inquiry has heard.

The third week of the hearing considering the resource consent application to build the flyover nex to the Basin Reserve kicked off this morning, with New Zealand Transport Agency expert David Dunlop facing questions from opposition lawyers.

Mr Dunlop, the principal transport planner for consultancy firm Opus, was asked to explain his assertion it would have a balanced affect on traffic volumes, despite saying there could be some extra traffic because of the flyover.

He said that while there may be some extra traffic, the project was part of a whole "package" including public transport improvements, which would counter balance that.

"I think it will be a balanced outcome ... a balanced provision and a balanced delivery of outcomes."

Just building the flyover would provide limited benefits for public transport, but by combining it with plans to create bus priority lanes there would be greater transport benefits, he said.

The four-person board of inquiry is considering whether to approve the $90 million flyover proposed by the New Zealand Transport Agency for 20 metres north of the Basin Reserve.

Mr Dunlop also answered questions about the benefits of the flyover to pedestrians and cyclists from Save the Basin lawyer Tom Bennion who argued that the bridge alone would make little difference for thoose groups.

"You didn't expect to see a substantial benefit from this bridge - this $5-$6 million bridge - from cycling or pedestrians until the second tunnel was built," he asked.Mr Dunlop agreed that was correct.